Analysis of the factors which have an influence on the reduction of residuary strengths due to alkaline solution in the interstitial mortars of concretes with aluminous cement Assessment of the risk limits in the case of roof beams

Abstract

The scarce references which exist in the bibliography on this subject and their vagueness on the factors which have an influence on the reduction of the strength of aluminous cement concrete due to the effect of alkalinity, have not yet allowed the limits to be clearly seen which could give rise to a situation of risk in the structural elements due to this cause. A study is presented which endeavors to measure the quantitative influence of different parameters of the same or of a similar conditions to those presented in the usual types of concrete in existing beams with aluminous cement characteristic of our market. The parameters tested were: the influence of the concentration of free ions OH^-, the class of alkaline ion, the temperature, the time, the presence or absence of CO₂, the degree of conversion, the physical parameters, porosities, densities, etc., and the phases existing were determined by XRD, DTA and TG before and after the alkaline action. From the results obtained in numerous series of Rilem mortars and micro-mortars, it is possible to see the possibility of establishing the setting of parameters which define areas without risk.